CS of out-of-flow positioned objects should have is_new_fc == true

third_party/WebKit/Source/core/layout/ng/ng_space_utils.cc

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/layout/ng/ng_space_utils.h"
 
 namespace blink {
 namespace {
 
 // Returns max of 2 {@code WTF::Optional} values.
 template <typename T>
 WTF::Optional<T> OptionalMax(const WTF::Optional<T>& value1,
                              const WTF::Optional<T>& value2) {
   if (value1 && value2) {
     return std::max(value1.value(), value2.value());
   } else if (value1) {
     return value1;
   }
   return value2;
 }
 
+bool isOutFlowPositioned(const EPosition& position) {

[ikilpatrick, 2017/03/23 16:39:59]

IsOutOfFlowPositioned

[Gleb Lanbin, 2017/03/24 20:10:05]

Done.

+  return position == EPosition::kAbsolute || position == EPosition::kFixed;
+}
+
 }  // namespace
 
 bool IsNewFormattingContextForInFlowBlockLevelChild(
     const NGConstraintSpace& space,
     const ComputedStyle& style) {
   // TODO(layout-dev): This doesn't capture a few cases which can't be computed
   // directly from style yet:
   //  - The child is a <fieldset>.
   //  - "column-span: all" is set on the child (requires knowledge that we are
   //    in a multi-col formatting context).
   //    (https://drafts.csswg.org/css-multicol-1/#valdef-column-span-all)
 
+  if (style.isFloating() || isOutFlowPositioned(style.position()))
+    return true;
+
   if (style.specifiesColumns() || style.containsPaint() ||
       style.containsLayout())
     return true;
 
   if (!style.isOverflowVisible())
     return true;
 
   EDisplay display = style.display();
   if (display == EDisplay::kGrid || display == EDisplay::kFlex ||
       display == EDisplay::kWebkitBox)
@@ skipping 29 matching lines @@
       return right_offset;
     case EClear::kBoth:
       return OptionalMax<LayoutUnit>(left_offset, right_offset);
     default:
       ASSERT_NOT_REACHED();
   }
   return WTF::nullopt;
 }
 
 }  // namespace blink